The use of composite materials is increasingly becoming the new norm for airframe construction. Many composite aircraft structures are made of monolithic laminates that are susceptible to inconsistencies, such as defects or damage. These inconsistencies may occur on the factory floor for just-manufactured structures during an aircraft build, as well as in the field for in-service aircraft. This may be equally true of structures in a number of contexts, such as in the context of structures of any of a number of manned or unmanned vehicles (e.g., motor vehicles, railed vehicles, watercraft, aircraft, spacecraft).
Primary composite structures may be designed to a positive compression after impact (CAI) margin based on specific impact energy levels. In practice, however, impact events may be complicated and impact energy may be unknown. When an impact event occurs, nondestructive inspection (NDI) procedures may be performed to determine the extent of some damage to or defect in a structure. In the case of ultrasonic inspection, the NDI data in the form of C-Scan images may be available to service engineers who have to disposition such damage/defect according to preset allowable damage limits (ADLs) defined in a structural repair manual (SRM).
Current techniques for defect and damage analysis may also be applicable to other types of inconsistencies, such as impact-induced delamination, topology change, heat-induced chemical change and the like. These techniques are highly-conservative processes, from interpretation of the NDI data to the analysis of the defective/damaged structure. And these highly-conservative processes can potentially lead to unnecessary rework (e.g., repair, replacement). It may therefore be desirable to have an apparatus and method that addresses these challenges, and improves upon existing practices while still ensuring continued airworthiness per regulatory requirements.